A capacitor is an electricity-holding device consisting of two close conductors sandwiced between a nonconductive dielectric.Its capacity to hold charge is often referred to simply as capacitance, denoted by the letter C.Capacitor is one of the most widely used electronic components in electronic equipment. It is widely used in circuit separation, coupling, bypass, filtering, tuning loop, energy conversion, control and so on.

Definition: consists of two metal electrodes sandwiced between a layer of insulating dielectric.When a voltage is applied between the two metal electrodes, the charge is stored on them, so a capacitor is an energy storage element.Any of two conductors insulated from each other and close to each other, forming a capacitor.The parallel plate capacitor consists of the electrode plate of the capacitor and the dielectric.

Features:

1. It has the charge-discharge characteristics and prevent the DC current flow through, allowing the ability of AC current through.

2. In the process of charging and discharging, the charge on the two plates has the accumulation process, that is, the voltage has the establishment process, therefore, the voltage on the capacitor can not sudden change.

Capacitor charging: the two plates respectively have the same amount of heterogeneous charge, the absolute value of the charge of each plate is called the charge of the capacitor.

Capacitor discharge: the positive and negative charges at the poles of a capacitor are neutralized through a wire.During the discharge, a brief current is generated on the conductor wire.

The reactance of a capacitor is inversely proportional to its frequency and capacity.That is, the analysis of capacitive reactance on the frequency of the signal, capacity size.